Science

If you have the patience to repeatedly switch an egg between a hot and a colder pan, you'll be rewarded with an amazing taste and texture, say physicists

A remarkable plesiosaur fossil reveals that the extinct reptiles had scales like modern sea turtles, unlike the ichthyosaurs that lived during the same period

New research suggests an impact recently rattled Mars deeper than thought.

HiRISE images a recent impact crater in the Cerberus Fossae region, seen on March 4, 2021. Credit: NASA/MRO/HiRISE

Something really rang the Red Planet’s bell. Research involving two NASA missions—the Mars Reconnaissance Orbiter, and the late InSight lander—has shed light on meteorite impacts and the seismic signals they produce. In a crucial finding, these signals may penetrate deeper inside Mars than previously thought. This could change how we view the interior of Mars itself.

The interior of Mars, and InSight’s detection of impacts versus geologic activity. Credit: NASA/JPL-Caltech.

The study comes from two papers published this week in the journal of Geophysical Research Letters. The primary data comes from NASA’s InSight mission, the first dedicated geodesy mission to Mars. Insight landed in the Elysium Planitia region of Mars on November 26th, 2018, and carried the first ever dedicated seismometer to the Red Planet. During its four years of operation, Insight detected over 1,300 ‘marsquakes,’ until the mission’s end in 2022. Most were due to geologic activity, while a few were due to distant meteorite impacts. Occasionally, InSight would even see ‘land tides’ due to the passage of the moon Phobos overhead.

InSight uses its robotic arm to place a wind shield over the SEIS seismometer. Credit: NASA/JPL-Caltech. A Distant Mars Impact

As on Earth, the detection of seismic waves gives us the opportunity to probe the interior of Mars, providing clues as to the density, depth and thickness of the crust, mantle and core. To be sure, impacts have been correlated to seismic waves captured by InSight in the past. A fresh crater seen by NASA’s Mars Reconnaissance Orbiter (MRO) in 2022 was correlated to an impact in the Amazonis Planitia region. But this was the first time an impact in the quake-prone Cerberus Fossae area was linked to InSight detections. The find is especially intriguing, as the area is quarter of a world away from the InSight landing site, at 1,640 kilometers (1,019 miles) distant.

A wider context view of the Cerberus Fossae region on Mars, courtesy of Mars Odyssey. NASA/JPL-Caltech.

The discovery of the 21.5-meter (71 foot) crater about the length of a semi-truck immediately presented scientists with a mystery. The smoking gun impact crater was more distant than thought. Typically, the Martian crust was thought to have a dampening effect on distant impacts. This means that the impact-generated waves took a more direct route via a ‘seismic highway,’ through the deeper mantle of the planet itself.

This discovery has key implications for what we generally think about the interior of Mars. This may also imply that our understanding and model for the planet’s interior may be due for an overhaul.

“Composition of the crust and how seismic waves from impacts travel through them is one factor,” Andrew Good (NASA-JPL) told Universe Today. “No current plans for follow-on seismometers on Mars, but there is a seismometer planned for the Moon in the near future,” says Good, in reference to the Farside Seismic Suite planned for 2026.

A New View of the Interior of Mars?

InSight team member Costantinos Charalambous of Imperial College London explains the finding in more detail, in an email to Universe Today:

The detection of this impact changes our understanding of Mars’ interior, particularly its crust and upper mantle, both immediately and in the longer term. However, in the latter case, it will take further work to know quite how!

The immediate shift in our understanding is that many more of the seismic events we detected at InSight have penetrated much deeper into the planet than we thought. Previously, we had thought that the crust would trap most of the high-frequency seismic energy, guiding it around the planet from the point of impact to InSight’s seismometer. We thought any high-frequency energy that penetrated more deeply into the mantle was quickly lost. But it now appears the Martian mantle is much better at propagating this seismic energy than we thought, allowing it to travel more quickly and farther. This tells us that the mantle has a different elemental composition that previously assumed, likely with a lower iron oxide content than earlier models predicted.

Additionally, because this impact was detected in Cerberus Fossae – a region where many recorded marsquakes likely originate – it provides a unique opportunity to distinguish seismic signatures generated by seismic activity driven by deeper, internal (tectonic) forces versus shallower, external (impact) sources.

Therefore, in the longer term, we will be re-examining the data from seismic events that we had previously assumed didn’t penetrate deeper into Mars. This work is ongoing, but these findings suggest new features of Mars’ upper mantle that we are seeking to confirm. Watch this space!

MRO’s Hunt For Impacts

Just how researchers imaged the tiny crater is the amazing second part of the story. NASA’s venerable MRO generates tens of thousands of images of the surface of Mars. These come mainly via the spacecraft’s onboard Context Camera. For years, researchers have used a machine learning algorithm to sift through the images. This looks for fresh impact sites that do not appear in previous frames. These areas are in turn flagged for closer scrutiny with the mission’s 0.5-meter High-Resolution Imaging Science Experiment (HiRISE) camera. The AI program was developed by NASA’s Jet Propulsion Laboratory.

A crater cluster on Mars, one of the first spotted courtesy the MRO AI search program. Credit: NASA/JPL-Caltech/MSSS.

To date, the team has found 123 new craters within 3,000 kilometers (1,864 miles) of the InSight landing site. 49 of these (including the Cerberus Fossae impact) are potential matches with InSight seismology data.

“Done manually, this would be years of work,” says InSight team member Valentin Bickel (University of Bern, Switzerland) in a recent press release. “Using this tool, we went from tens of thousands of images to just a handful in a matter of days.”

InSight’s Legacy

InSight provided a wealth of seismology and geological information about Mars. The Seismic Experiment for Interior Structure (SEIS) instrument worked as planned. The Heat Flow and Physical Properties Package (HP^3) failed, however, to reach its target depth for returning useful science about the planet’s interior. Unfortunately, no dedicated follow on geology mission is set to head to Mars. This sort of exciting science will probably have to wait until the hoped for crewed missions of the 2030s.

InSight was a collaborative effort between NASA, the German Space Agency (DLR) and the French Space Agency (CNES). Other international partners also participated in the ground-breaking mission.

Still, it’s great to see missions like InSight still generating scientific results, long after they’ve fallen silent.

The post A Recent Impact on Mars Shook the Planet to Its Mantle appeared first on Universe Today.

A lidar scanner has a resolution so high it can image ridges and indentations of only 1 millimetre on objects hundreds of metres away – and capture objects as distant as 1 kilometre

When the electron, the first subatomic particle to be identified, was discovered in 1897, it was thought to be a tiny speck with electric charge, moving around on a path governed by the forces of electricity, magnetism and gravity. This was just as one would expect for any small object, given the incredibly successful approach to physics that had been initiated by Galileo and Newton and carried onward into the 19th century.

But this view didn’t last long. Less than 15 years later, physicists learned that an atom has a tiny nucleus with positive electric charge and most of an atom’s mass. This made it clear that something was deeply wrong, because if Newton’s and Maxwell’s laws applied, then all the electrons in an atom should have spiraled into the nucleus in less than a second.

From 1913 to 1925, physicists struggled toward struggled toward a new vision of the electron. They had great breakthroughs and initial successes in the late 1920s. But still, something was off. They did not really find what they were looking for until the end of the 1940s.

Most undergraduates in physics, philosophers who are interested in physics, and general readers mainly learn about quantum physics of the 1920s, that of Heisenberg, Born, Jordan and of Schrödinger. The methods developed at that time, often called “quantum mechanics” for historical reasons, represented the first attempt by physicists to make sense of the atomic, molecular, and subatomic world. Quantum mechanics is all you need to know if you just want to do chemistry, quantum computing, or most atomic physics. It forms the basis of many books about the applications of quantum physics, including those read by most non-experts. The strange puzzles of quantum physics, including the double-slit experiment that I reviewed recently, and many attempts to interpret or alter quantum physics, are often phrased using this 1920s-era approach.

What often seems to be forgotten is that 1920s quantum physics does not agree with data. It’s an approximation, and sometimes a very good one. But it is inconsistent with Einstein’s relativity principle, a cornerstone of the cosmos. This is in contrast to the math and concepts that replaced it, known as relativistic quantum field theory. Importantly, electrons in quantum field theory are very different from the electrons of the 1920s.

And so, when trying to make ultimate conceptual sense of the universe, we should always be careful to test our ideas using quantum field theory, not relying on the physics of the 1920s. Otherwise we risk developing an interpretation which is inconsistent with data, at a huge cost in wasted time. Meanwhile, when we do use the 1920s viewpoint, we should always remember its limitations, and question its implications.

Overview

Before I go into details, here’s an overview.

I have argued strongly in my book and on this blog that calling electrons “particles” is misleading, and one needs to remember this if one wants to understand them. One might instead consider calling them “wavicles“, a term itself from the 1920s that I find appropriate. You may not like this term, and I don’t insist that you adopt it. What’s important is that you understand the conceptual point that the term is intended to convey.

Most crucially, electrons as wavicles is an idea from quantum field theory, not from the 1920s (though a few people, like de Broglie, were on the right track.) In the viewpoint of 1920s quantum physics, electrons are not wavicles. They are particles. Quantum particles.

Before quantum physics, an electron was described as an object with a position and a velocity (or a momentum, which is the electron’s mass times its velocity), moving through the world along a precise path. But in 1920s quantum physics, an electron is described as a particle with a position or a momentum, or some compromise between the two; its path is not definite.

In Schrödinger’s viewpoint [and I emphasize that there are others — his approach is just the most familiar to non-experts], there is a quantum wave function (or more accurately, a quantum state) that tells us the probabilities for the particle’s behavior: where we might find it, and where it might be going.

A wave function must not be identified with the particle itself. No matter how many particles there are, there is only one wave function. Specifically, if there are two electrons, then a single quantum wave function tells us the probabilities for their joint behavior — for the behavior of the system of two electrons. The two electrons are not independent of one another; in quantum physics I can’t say what one’s behavior might be without worrying about what the other is doing. The wave function describes the two electrons, but it is not either one of them.

Then we get to quantum field theory of the late 1940s and beyond. Now we view an electron as a wave — as a ripple in a field, known as the electron field. The whole field, across all of space, has to be described by the wave function, not just the one electron. (In fact, that’s not right either: our wave function has to simultaneously describe all the universe’s fields.) This is very different conceptually from the ’20s; the electron is never an object with a precise position, and instead it is generally spread out.

So it’s really, really important to remember that it is relativistic quantum field theory that universally agrees with experiments, not the quantum physics of the ’20s. If we forget this, we risk drawing wrong conclusions from the latter. Moreover, it becomes impossible to understand what modern particle physicists are talking about, because our description of the physics of “particles” relies on relativistic quantum field theory.

The Electron Over Time

Let me now go into more detail, with hope of giving you some intuition for how things have changed from 1900 to 1925 to 1950.

1900: Electrons Before Quantum Physics A Simple Particle

Pre-quantum physics (such as one learns in a first-year undergraduate course) treats an electron as a particle with a definite position which changes in a definite way over time; it has a definite speed v which represents the rate of the change of its motion. The particle also has definite momentum p equal to its mass m times its speed v. Scientists call this a “classical particle”, because it’s what Isaac Newton himself, the founder of old-school (“classical”) physics would have meant by the word “particle”.

Figure 1: A classical particle (blue dot) moves across across physical space. At the moment shown, it is at position A, and its path takes it to the right with a definite velocity. Two Simple Particles

Two particles are just two of these objects. That’s obvious, right? [Seems as though it ought to be. But as we’ll see, quantum physics says that not only isn’t it obvious, it’s false.]

Figure 2: Two particles, each traveling independently on its own path. Particle 1 moves rapidly to the right and is located at A, while particle 2 moves slowly to the left and is located at B. Two Particles in the “Space of Possibilities”

But now I’m going to do something that may seem unnecessarily complicated — a bit mind-bending for no obvious purpose. I want to describe the motion of these two particles not in the physical space in which they individually move but instead in the space of possibilities for two-particle system, viewed as a whole.

Why? Well, in classical physics, it’s often useful, but it’s also unnecessary. I can tell you where the two particles are in physical space and be done with it. But it quantum physics I cannot. The two particles do not, in general, exist independently. The system must be viewed as a whole. So to understand how quantum physics works, we need to understand the space of possibilities for two classical particles.

This isn’t that hard, even if it’s unfamiliar. Instead of depicting the two particles as two independent dots at two locations A and B along the line shown in Fig. 2, I will instead depict the system by indicating a point in a two-dimensional plane, where

• the horizontal axis depicts where the first particle is located
• the vertical axis depicts where the second particle is located

To make sure that you remember that I am not depicting any one particle but rather the system of two particles, I have drawn what the system is doing at this moment as a star in this two-dimensional space of possibilities. Notice the star is located at A along the horizontal axis and at B along the vertical axis, indicating that one particle is at A and the other is at B.

Figure 3: Within the space of possibilities, the system shown in Fig. 2 is located at the star, where the horizontal axis (the position of particle 1) is at A and the vertical axis (the position of the particle 2) is at B. Over time the star is moving to the right and downward, as shown by the arrow, indicating that in physical space particle 1 moves to the right and the particle 2 to the left, as shown in Fig. 2.

Moreover, in contrast to the two arrows in physical space that I have drawn in Fig. 2, each one indicating the motion of the corresponding particle, I have drawn a single arrow in the space of possibilities, indicating how the system is changing over time. As you can see from Fig. 2,

• the first particle is moving from A to the right in physical space, which corresponds to rightward motion along the horizontal axis of Fig. 3;
• the second particle is moving from B to the left in physical space, which corresponds to downward motion along the vertical axis in Fig. 3;

and so the arrow indicating how the system is changing over time points downward and to the right. It points more to the right than downward, because the motion of the particle at A is faster than the motion of the particle at B.

Why didn’t I bother to make a version of Fig. 3 for the case of just one particle? That’s because for just one particle, physical space and the space of possibilities are the same, so the pictures would be identical.

I suggest you take some time to compare Figs. 2 and 3 until the relationship is clear. It’s an important conceptual step, without which even 1920s quantum physics can’t make sense.

If you’re having trouble with it, try this post, in which I gave another example, a bit more elaborate but with more supporting discussion.

1925: Electrons in 1920s Quantum Physics A Quantum Particle

1920s quantum physics, as one learns in an upper-level undergraduate course, treats an electron as a particle with position x and momentum p that are never simultaneously definite, and both are generally indefinite to a greater or lesser degree. The more definite the position, the less definite the momentum can be, and vice versa; that’s Heisenberg’s uncertainty principle applied to a particle. Since these properties of a particle are indefinite, quantum physics only tells us about their statistical likelihoods. A single electron is described by a wave function (or “state vector”) that gives us the probabilities of it having, at a particular moment in time, a specific location x0 or specific momentum p0. I’ll call this a “quantum particle”.

How can we depict this? For a single particle, it’s easy — so easy that it’s misleading, as we’ll see when we go to two particles. All we have to do is show what the wave function looks like; and the wave function [actually the square of the wave function] tells us about the probability of where we might find the particle. This is indicated in Fig. 4.

Figure 4: A quantum particle corresponding to Fig. 1. The probability of finding the particle at any particular position is given by the square of a wave function, here sketched in red (for wave crests) and blue (for wave troughs). Rather than the particle being at the location A, it may be somewhere (blue dot) near A , but it could be anywhere where the wave function is non-zero. We can’t say exactly where (hence the question mark) without actually measuring, which would change the wave function.

As I mentioned earlier, the case of one particle is special, because the space of possibilities is the same as physical space. That’s potentially misleading. So rather than think too hard about this picture, where there are many potentially misleading elements, let’s go to two particles, where things look much more complicated, but are actually much clearer once you understand them.

Two Quantum Particles

Always remember: it’s not one wave function per particle. It’s one wave function for each isolated system of particles. Two electrons are also described by a single wave function, one that gives us the probability of, say, electron 1 being at location A while electron 2 is simultaneously at location B. That function cannot be expressed in physical space! It can only be expressed in the space of possibilities, because it never tells us the probability of finding the first electron at position 1 independent of what electron 2 is doing.

In other words, there is no analogue of Fig. 2. Quantum physics is too subtle to be squeezed easily into a description in physical space. Instead, all we can look for is a generalization of Fig. 3.

And when we do, we might find something like what is shown in Fig. 5; in contrast to Fig. 4, where the wave function gives us a rough idea of where we may find a single particle, now the wave function gives us a rough idea of what the system of two particles may be doing — and more precisely, it gives us the probability for any one thing that the two particles, collectively, might be doing. Compare this figure to Fig. 2.

Figure 5: The probability of finding the two-particle system at any given point in the space of possibilities is given by the square of a wave function, shown again in red (wave crests) and blue (wave troughs). We don’t know if the positions of the two particles is as indicated by the star (hence the question mark), but the wave function does tell us the probability that this is the case, as well as the probability of all other possibilities.

In Fig. 2, we know what the system is doing; particle 1 is at position A and particle 2 is at position B, and we know how their positions are changing with time. In Fig. 5 we know the wave function and how it is changing with time, but the wave function only gives us probabilities for where the particles might be found — namely that they are near position A and position B, respectively, but exactly can’t be known known until we measure, at which point the wave function will change dramatically, and all information about the particles’ motions will be lost. Nor, even though roughly that they are headed right and left respectively, we can’t know exactly where they are going unless we measure their momenta, again changing the wave function dramatically, and all information about the particles’ positions will be lost.

And again, if this is too hard to follow, try this post, in which I gave another example, a bit more complicated but with more supporting discussion.

1950: Electrons in Modern Quantum Field Theory

1940s-1950s relativistic quantum field theory, as a future particle physicist typically learns in graduate school, treats electrons as wave-like objects — as ripples in the electron field.

[[[NOTA BENE: I wrote “the ElectrON field”, not “the electrIC field”. The electrIC field is something altogether different!!!]

The electron field (like any cosmic field) is found everywhere in physical space.

(Be very careful not to confuse a field, defined in physical space, with a wave function, which is defined on the space of possibilities, a much larger, abstract space. The universe has many fields in its physical space, but only one wave function across the abstract space of all its possibilities.)

In quantum field theory, an electron has a definite mass, but as a ripple, it can be given any shape, and it is always undergoing rapid vibration, even when stationary. It does not have a position x, unlike the particles found in 1920s quantum field theory, though it can (very briefly) be shaped into a rather localized object. It cannot be divided into pieces, even if its shape is very broadly spread out. Nevertheless it is possible to create or destroy electrons one at a time (along with either a positron [the electron’s anti-particle] or an anti-neutrino.) This rather odd object is what I would mean by a “wavicle”; it is a particulate, indivisible, gentle wave.

Meanwhile, there is a wave function for the whole field (really for all the cosmic fields at once), and so that whole notion is vastly more complicated than in 1920s physics. In particular, the space of possibilities, where the wave function is defined, is the space of all possible shapes for the field! This is a gigantic space, because it takes an infinite amount of information to specify a field’s shape. (After all, you have to tell me what the field’s strength is at each point in space, and there are an infinite number of such points.) That means that the space of possibilities now has an infinite number of dimensions! So the wave function is a function of an infinite number of variables, making it completely impossible to draw, generally useless for calculations, and far beyond what any human brain can envision.

It’s almost impossible to figure out how to convey all this in a picture. Below is my best attempt, and it’s not one I’m very proud of. Someday I may think of something better.

Figure 6: In quantum field theory — in contrast to “classical” field theory — we generally do not know the shape of the field (its strength, or “value”, shown on the vertical axis, at each location in physical space, drawn as the horizontal axis.) Instead, the range of possible shapes is described by a wave function, not directly shown. One possible shape for a somewhat localized electron, roughly centered around the position A, is shown (with a question mark to remind you that we do not know the actual shape.) The blue blur is an attempt to vaguely represent a wave function for this single electron that allows for other shapes, but with most of those shapes somewhat resembling the shape shown and thus localized roughly around the position A. [Yeah, this is pretty bad.]

I’ve drawn the single electron in physical space, and indicated one possible shape for the field representing this electron, along with a blur and a question mark to emphasize that we don’t generally know the shape for the field — analogous to the fact that when I drew one electron in Fig. 4, there was a blur and question mark that indicated that we don’t generally know the position of the particle in 1920s quantum physics.

[There actually is a way to draw what a single, isolated particle’s wave function looks like in a space of possibilities, but you have to scramble that space in a clever way, far beyond what I can explain right now. We’ll see it later this year.]

Ugh. Writing about quantum physics, even about non-controversial issues, is really hard. The only thing I can confidently hope to have conveyed here is that there is a very big difference between electrons as they were understood and described in 1920’s quantum physics and electrons as they are described in modern quantum field theory. If we get stuck in the 1920’s, the math and concepts that we apply to puzzles like the double slit experiment and “spooky action at a distance” are never going to be quite right.

As for what’s wrong with Figure 6, there are so many things, some incidental, some fundamental:

• The picture I’ve drawn would be somewhat accurate for a Higgs boson as a ripple in the Higgs field. But an electron is a fermion, not a boson, and trying to draw the ripple without being misleading is kind of impossible.
• The electron field is given by a complex numbers, and in fact more than one, so drawing it as though it has a shape like the one shown in Fig. 6 is an oversimplification.
• At best, Fig. 6 sketches how an electron would look if it didn’t experience any forces. But because electrons are electrically charged and do experience electric and magnetic forces, we can’t just show the electron field without showing the electromagnetic field too; the wave function for an electron deeply involves both. That gets super-complicated.
• The wave function is suggested by a vague blur, but in fact it always has more structure than can be depicted here.
• And there are probably more issues, as I’m sure some readers will point out. Go ahead and do so; it’s better to state all the flaws out loud.

What about two electrons — two ripples in the electron field? This is currently beyond my abilities to sketch. Even ignoring the effects of electric and magnetic forces, describing two electrons in quantum field theory in a picture like Fig. 6 seems truly impossible. For one thing, because electrons are precisely identical in quantum field theory, there are always correlations between the two electrons that cannot be avoided — they can never be independent, in the way that two classical electrons are. (In fact this correlation even affects Fig. 5; I ignored this issue to keep things simpler.) So they really cannot be depicted in physical space. But the space of possibilities is far too enormous for any depiction (unless we do some serious rescrambling — again, something for later in the year, and even then it will only work for bosons.)

And what should you take away from this? Some things about quantum physics can be understood using 1920’s language, but not the nature of electrons and other elementary “particles”. When we try to extract profound lessons from quantum physics without using quantum field theory, we have to be very careful to make sure that those lessons still apply when we try to bring them to the cosmos we really live in — a cosmos for which 1920’s quantum physics proved just as imperfect, though still useful, as the older laws of Newton and Maxwell.

The risk of asteroid 2024 YR4 hitting Earth seems to be creeping up as astronomers gather more data, but does that mean we should be scrambling to prepare for an impact in 2032?

When it comes to vaccines: “If it exists we resist.” 

The post We are not antivaccine, we are pro unattainable vaccine first appeared on Science-Based Medicine.

Astronomers have succeeded in observing the magnetic field around a young star where planets are thought to be forming. The team was able to use dust to measure the three-dimensional structure 'fingerprint' of the magnetic field. This will help improve our understanding of planet formation.

Using a pioneering artificial intelligence platform, researchers have assessed whether a cardiac AI tool recently trialed in South Australian hospitals actually has the potential to assist doctors and nurses to rapidly diagnose heart issues in emergency departments.

A group of male koalas were filmed grooming and playing together, in contrast to their solitary reputation, probably as a result of an unusually dense population in southern Victoria

Set to enter hospice care, a patient with idiopathic multicentric Castleman's disease is now in remission after treatment with a medication identified by an AI-guided analysis.

The current exoplanet census contains 5,832 confirmed candidates, with more than 7,500 still awaiting confirmation. Of those that have been confirmed, most have been gas giants ranging from Neptune-like bodies (1992) to those similar to or many times the size and mass of Jupiter and Saturn (1883). Like the gas giants of the Solar System, astronomers generally theorized that these types of planets form in the outer reaches of their star system, where conditions are cold enough for gases like hydrogen and helium and volatile compounds (water, ammonia, methane, etc.) will condense or freeze solid.

However, astronomers have noted that many of the gas giants they’ve observed orbited close to their stars, known as “Hot Jupiters.” This has raised questions about whether or not gas giants and other planets migrate after formation until they find their long-term, stable orbits. In a new study, a team from Arizona State University’s School Of Earth and Space Exploration (ASU-SESE) examined the atmospheric chemistry of several Hot and Ultra-Hot Jupiters. After examining WASP-121b, the team came to the unexpected conclusion that it likely formed close to its star.

The research was conducted by Graduate Associate Peter C. B. Smith and other members of the ASU-SESE. They were joined by exoplanet researchers from the Steward Observatory, the Italian National Institute for Astrophysics (INAF), the Trottier Institute for Research on Exoplanets (iREX), the Centre for Exoplanets and Habitability (CEH), and multiple universities. Collectively, they are part of the Roasting Marshmallows Program, and their latest research was presented in a paper appearing in The Astronomical Journal.

Members of this program are dedicated to studying the atmospheres of hot and ultra-hot Jupiters using the Immersion GRating INfrared Spectrograph (IGRINS), built by the University of Texas and the Korea Astronomy and Space Science Institute (KASI). The instrument is part of the Gemini South telescope in Chile, one of two telescopes that make up the International Gemini Observatory, funded in part by the U.S. National Science Foundation (NSF) and operated by the National Optical-Infrared Astronomy Research Laboratory (NOIRLab).

This program aims to learn more about the protoplanetary disks from which hot gas giants formed. In the past, scientists assumed that these disks – leftover rocky and icy material from the nebulae that give birth to stars – settle into gradients around their suns that allow certain types of planets to form around them. According to this theory, material closer to the star would consist largely of rocky material since volatiles would turn to vapor, while material farther from the star would consist of icy material since temperatures would be low enough for it to solidify.

Since the material in these disks varies based on the distance from their parent stars, astronomers can measure the abundance of these materials in planetary atmospheres based on their spectral signatures. As a result, they can determine how far from a parent star its planets may have formed. Ordinarily, measuring this ratio requires multiple observations in both visible and infrared light (for rocky and gaseous elements, respectively). However, the team obtained measurements WASP-121b to determine the radio of rocky and gaseous elements thanks to it being an ultra-hot Jupiter.

As a result, the planet’s atmosphere contains vaporized rock and gaseous materials that were detectable using the IGRINS instrument alone and with a single observation! This instrument allowed the team to obtain high-resolution spectral data from WASP-121b as it made a transit in front of its star. Said Smith:

“Ground-based data from Gemini South using IGRINS actually made more precise measurements of the individual chemical abundances than even space-based telescopes could have achieved. Our measurement means that perhaps this typical view needs to be reconsidered and our planet formation models revisited. The planet’s dayside is so hot that elements typically thought of as ‘metal’ are vaporized into the atmosphere, making them detectable via spectroscopy.”

This artist’s impression shows an ultra-hot exoplanet as it is about to transit in front of its host star.
Credit: ESO

The spectra showed that WASP-121b has a high rock-to-ice ratio, indicating that it accreted an excess of rocky material while forming. This suggests the planet formed closer to its star, which was quite a surprise since traditional models suggest that gas giants need much colder temperatures to form. The reason for this became obvious once Smith and his team learned several things about WASP-121b’s atmosphere. On the dayside, temperatures are so hot that rocky material and metals are vaporized into the atmosphere, while powerful winds blow these to the night side, where they condense.

This leads to WASP-121b experiencing many types of “metal rain” on its night side, a phenomenon that astronomers had previously observed. “The climate of this planet is extreme and nothing like that of Earth,” said Smith, adding that IGRINS was a major factor in his team’s detailed measurements. “Our instrument sensitivity is advancing to the point where we can use these elements to probe different regions, altitudes, and longitudes to see subtleties like wind speeds, revealing just how dynamic this planet is.”

These results may resolve the mystery of Hot Jupiters by demonstrating that gas giants need not be composed predominantly of gaseous volatile elements, but heavier elements that are heated to the point that they become vapor. These findings support previous observations of gas giants that experience metal precipitation, such as WASP-76, Kepler-7b, KELT-9b. The team hopes that future surveys using IGRINS successor instrument – IGRINS-2 – which was commissioned for the Gemini North telescope in Hawai‘i and is currently being calibrated for science operations.

Further Reading: NOIRLab, The Astronomical Journal

The post This Hot Jupiter Probably Formed Close to Its Star appeared first on Universe Today.

A temporary loss of access to key datasets on levels of CO2 in the atmosphere added to concern about the potential fallout of the Trump administration’s attacks on climate science

Is it possible to understand the Universe without understanding the largest structures that reside in it? In principle, not likely. In practical terms? Definitely not. Extremely large objects can distort our understanding of the cosmos.

Astronomers have found the largest structure in the Universe so far, named Quipu after an Incan measuring system. It contains a shocking 200 quadrillion solar masses.

Astronomy is an endeavour where extremely large numbers are a part of daily discourse. But even in astronomy, 200 quadrillion is a number so large it’s rarely encountered. And if Quipu’s extremely large mass doesn’t garner attention, its size surely does. The object, called a superstructure, is more than 400 megaparsecs long. That’s more than 1.3 billion light-years.

A structure that large simply has to affect its surroundings, and understanding those effects is critical to understanding the cosmos. According to new research, studying Quipu and its brethren can help us understand how galaxies evolve, help us improve our cosmological models, and improve the accuracy of our cosmological measurements.

The research, titled “Unveiling the largest structures in the nearby Universe: Discovery of the Quipu superstructure,” has been accepted for publication in the journal Astronomy and Astrophysics. Hans Bohringer from the Max Planck Institute is the lead author.

“For a precise determination of cosmological parameters, we need to understand the effects of the local large-scale structure of the Universe on the measurements,” the authors write. “They include modifications of the cosmic microwave background, distortions of sky images by large-scale gravitational lensing, and the influence of large-scale streaming motions on measurements of the Hubble constant.”

Superstructures are extremely large structures that contain groups of galaxy clusters and superclusters. They’re so massive they challenge our understanding of how our Universe evolved. Some of them are so massive they break our models of cosmological evolution.

Quipu is the largest structure we’ve ever found in the Universe. It and the other four superstructures the researchers found contain 45% of the galaxy clusters, 30% of the galaxies, 25% of the matter, and
occupy a volume fraction of 13%.

The image below helps explain why they named it Quipu. Quipu are recording devices made of knotted cords, where the knots contain information based on colour, order, and number. “This view gives the best impression of the superstructure as a long filament with small side filaments, which initiated the naming of Quipu,” the authors explain in their paper.

This figure from the new research is a wedge diagram in declination and distance of the Quipu superstructure. The distance is in units of Megaparsecs. The red dots show the superstructure members and the black lines show the friends-to-friends linking. The grey dots show the non-member clusters. The two dashed lines give the distances for redshifts of 0.03 and 0.06.

In their work, Bohringer and his co-researchers found Quipu and four other superstructures within a distance range of 130 to 250 Mpc. They used X-ray galaxy clusters to identify and analyze the superstructures in their Cosmic Large-Scale Structure in X-rays (CLASSIX) Cluster Survey. X-ray galaxy clusters can contain thousands of galaxies and lots of very hot intracluster gas that emits X-rays. These emissions are the key to mapping the mass of the superstructures. X-rays trace the densest regions of matter concentration and the underlying cosmic web. The emissions are like signposts for identifying superstructures.

This figure from the research shows galaxy distribution in density gradients. The density ratio to the average density is shown by six contour levels: 0 – 0.23 (black), 0.23 – 0.62 (dark blue), 0.62 – 1.13 (light blue), 1.13 – 1.9 (grey), 1.9 – 3.7 (olive), and > 3.7 (white). The clusters of the five superstructures are overplotted with filled black circles. Image Credit: Bohringer et al. 2025.

The authors point out that “the difference in the galaxy density around field clusters and members of superstructures is remarkable.” This could be because field clusters are populated with less massive clusters than those in the superstructure rather than because the field clusters have lower galaxy density.

Regardless of the reasons, the mass of these superstructures wields enormous influence on our attempt to observe, measure, and understand the cosmos. “These large structures leave their imprint on cosmological observations,” the authors write.

The superstructures leave an imprint on the Cosmic Microwave Background (CMB), which is relic radiation from the Big Bang and key evidence supporting it. The CMB’s properties match our theoretical predictions with near-surgical precision. The superstructures’ gravity alters the CMB as it passes through them according to the Integrated Sachs-Wolfe (ISW) effect, producing fluctuations in the CMB. These fluctuations are foreground artifacts that are difficult to filter out, introducing interference into our understanding of the CMB and, hence, the Big Bang.

The full-sky image of the temperature fluctuations (shown as colour differences) in the cosmic microwave background is made from nine years of WMAP observations. These are the seeds of galaxies from a time when the universe was under 400,000 years old. Credit: NASA/WMAP

The superstructures can also impact measurements of the Hubble constant, a fundamental value in cosmology that describes how fast the Universe is expanding. While galaxies are moving further apart due to expansion, they also have local velocities, called peculiar velocities or streaming motions. These need to be separated from expansion to understand expansion clearly. The great mass of these superstructures influences these streaming motions and distorts our measurements of the Hubble constant.

The research also notes that these massive structures can alter and distort our sky images through large-scale gravitational lensing. This can introduce errors in our measurements.

On the other hand, simulations of the Lambda CDM produce superstructures like Quipu and the four others. Lambda CDM is our standard model of Big Bang cosmology and accounts for much of what we see in the Universe, like its large-scale structure. “We find superstructures with similar properties in simulations based on Lambda-CDM cosmology models,” the authors write.

It’s clear that these superstructures are critical to understanding the Universe. They hold a significant portion of its matter and affect their surroundings in fundamental ways. More research is needed to understand them and their influence.

“Interesting follow-up research on our findings includes, for example, studies of the influence of these environments on the galaxy population and evolution,” the authors write in their conclusion.

According to the study, these superstructures won’t persist forever. “In the future cosmic evolution, these superstructures are bound to break up into several collapsing units. They are thus transient configurations,” Bohringer and his co-researchers explain.

“But at present, they are special physical entities with characteristic properties and special cosmic environments deserving special attention.”

The post Astronomers Find the Largest Structure in the Universe and Name it “Quipu” appeared first on Universe Today.

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